Information receiving device and method, information release device, and information communication system

ABSTRACT

If an instruction is provided so as to receive second content information in place of first content information on the basis of only one operation by a user while the first content information is received through a connection formed in a communication network, the connection for communication of the first content information is disconnected, and thereafter, a connection for communication of the second content information is formed. In this manner, network resources can be reserved or released without consciousness of users.

TECHNICAL FIELD

The present invention relates to an information receiving apparatus, aninformation receiving method, an information providing apparatus, and aninformation communication system, by which a user can reserve or releasea resource without consciousness.

BACKGROUND ART

It is considered that users can use a high-speed network in homes in thenear future, for example, owing to progress of FTTH (Fiber to the Home)techniques which provides various communication services such astelephone, ISDN, and the like through optical fiber cables extended tohomes. In case of realizing data providing services which are expectedto spread under this environment, such as Internet television service(which will be abbreviated as Internet TV hereinafter), Internet videoon demand service (which will be abbreviated as Internet VoD), and thelike, the service providers must guarantee the quality of data providedfor users, i.e., the quality of services (QoS). In order to guaranteethe quality in the data providing services, reservations of bandresources used on the network must be carried out to achieve dataproviding services. That is, to explain an IP (Internet Protocol)network using an ATM (Asynchronous Transfer Mode), a connectionless IPpacket needs to be transferred by a virtual connection (which will beabbreviated as VC hereinafter) as a connection-oriented technique whichguarantees the quality.

Meanwhile, RSVP (Resource reSerVation Protocol) has been conventionallyknown as a protocol for reserving a resource such as virtual connection(VC) or the like. In the RSVP, a user operates a terminal connected to anetwork to reserve a resource, and a connection is thereby constructed.In this manner, the user can obtain data providing services. Also, inthe RSVP, after a data providing service is obtained, the resource needsto be released when the user operates the terminal again and theconnection needs to be cut.

Thus, in a conventional protocol such as RSVP for reserving a resource,a user himself or herself must operate a terminal, for example, toreserve or release a resource. Thus, there is a problem that users mustcarry burdens.

Also, for example, in case of an Internet TV, broadcasting of programsis expected to be supplied through a plurality of channels. In the dataproviding service (program broadcasting service) by the internet TV, itis considered that a user will switch channels to know what programs arebeing broadcasted, like watching and hearing a normal televisionbroadcasting program, i.e., a user will frequently switch channels forzapping. In this case, however, the user must operate a terminal toreserve or release a resource every time zapping is carried out, so thatthis operation will become a large burden for the user.

The present invention has been made in view of this situation, and hasan object of providing an information receiving apparatus, aninformation receiving method, an information providing apparatus, and aninformation communication system, by which users can reserve or releaseresources without particular consciousness.

DISCLOSURE OF THE INVENTION

An information receiving apparatus according to the present invention,which is connected to an information providing apparatus by forming aconnection in a communication network and which receives contentinformation from the information providing apparatus through theconnection, comprises: input means for inputting a command based on anoperation by a user; communication means for making communicationthrough the communication network; control means for controlling thecommunication means so as to output an instruction signal, based on thecommand inputted through the input means; and display means fordisplaying the content information received by the communication means,characterized in that if a switching instruction which indicates thatsecond content information should be received in place of first contentinformation is inputted as the command to the communication means whenthe communication means is receiving the first content informationthrough the connection formed in the communication network, the controlmeans makes control so as to output a disconnection instruction fordisconnecting the connection for transmitting the first contentinformation, which is formed in the communication network connecting thecommunication means and the information providing apparatus, and aformation instruction for forming the connection for transmitting thesecond content information, which is formed in the communication networkconnecting the communication means and the information providingapparatus.

The control means of the information receiving apparatus according tothe present invention controls makes control such that the communicationmeans outputs a reservation instruction signal for making reservation ofa communication band resource of the communication network, as theinstruction signal, prior to formation of the connection.

Also, if the control means of the information receiving apparatusaccording to the present invention recognizes the communication bandresource which is necessary for the content information to be received,the control means makes control such that the communication meansoutputs the reservation instruction signal containing resourceinformation indicating the communication band resource, or if thecontrol means does not recognize the communication band resource whichis necessary for the content information to be received, the controlmeans makes control such that the communication means outputs thereservation instruction signal without containing the resourceinformation indicating the communication band resource.

Also, the information receiving apparatus according to the presentinvention further comprises storage means for storing predeterminedresource information used for reserving a communication band resourcenecessary for transmitting the content information, characterized inthat the control means generates the formation instruction containingthe predetermined resource information stored in the storage means, whenforming the connection.

Also, the information receiving apparatus according to the presentinvention is characterized in that the storage means stores informationused for reserving a communication band resource for transmitting thecontent information to be provided at least in a one-to-one manner or aone-to-many manner, as the predetermined resource information.

Also, the information receiving apparatus according to the presentinvention is characterized in that after outputting the disconnectioninstruction for instructing disconnection of the connection for contentinformation presently received at a previously set time interval, thecontrol means makes control so as to output the formation instructionfor instructing formation of the connection for transmitting contentinformation according to a previously set order.

Next, an information receiving method according to the presentinvention, in which a connection is made in a communication network toan information providing apparatus and content information is receivedfrom the information providing apparatus through the connection,comprises: an input step of inputting a command based on an operation bya user; a communication step of making communication through thecommunication network; a control step of controlling the communicationstep so as to output an instruction signal, based on the commandinputted through the input step; and a display step of displaying thecontent information received through the communication step,characterized in that if a switching command which instructs that secondcontent information should be received in place of first contentinformation is inputted as the command in the communication step, basedon only one operation by a user in the input step, when the firstcontent information is being received in the communication step throughthe connection formed in the communication network, the control stepmakes control so as to output a disconnection instruction forinstructing disconnection of the connection for transmitting the firstcontent information, which is formed in the communication networkconnected with the information providing apparatus by the communicationstep, and a formation instruction for instructing formation of theconnection for transmitting the second content information, which isformed in the communication network connected with the informationproviding apparatus in the communication step.

The control step of the information receiving method according to thepresent invention makes control such that a reservation instructionsignal for making reservation of a communication band resource of thecommunication network is outputted as the instruction signal in thecommunication step, prior to formation of the connection.

Also, if the communication band resource which is necessary for thecontent information to be received is recognized in the control step,the control step of the information receiving method according to thepresent invention makes control such that the reservation instructionsignal containing resource information indicating the communication bandresource is outputted in the communication step, or if the communicationband resource which is necessary for the content information to bereceived is not recognized in the control step, the control step makescontrol such that the reservation instruction signal without containingresource information indicating the communication band resource isoutputted in the communication step.

Also, the information receiving method according to the presentinvention further comprises a storage step of storing predeterminedresource information used for reserving a communication band resourcenecessary for transmitting the content information, characterized inthat the control step generates the formation instruction containing thepredetermined resource information stored in the storage step, whenforming the connection.

Also, information used for reserving a communication band resource fortransmitting the content information to be provided at least in aone-to-one manner or a one-to-many manner is stored as the predeterminedresource information in the storage step of the information receivingmethod according to the present invention.

Also, after outputting the disconnection instruction for instructingdisconnection of the connection for content information presentlyreceived, at a previously set time interval, the control step of theinformation receiving method according to the present invention makescontrol so as to output the formation instruction for instructingformation of the connection for transmitting content informationaccording to a previously set order.

Next, an information providing apparatus according to the presentinvention, which is connected to an information receiving apparatusthrough a communication network and which provides the informationreceiving apparatus with content information with use of a communicationband resource of the communication network which is reserved prior toproviding of the content information, comprises: communication means formaking communication through the communication network; storage meansfor storing the content information; detection means for detectingwhether or not resource information indicating the communication bandresource is contained in an instruction signal, when the communicationmeans receives the instruction signal from the information receivingapparatus; and control means for outputting a band reservation commandfor reserving the communication band resource, based on a detectionresult from the detection means, and for making control to make aselection from a first mode in which the communication means iscontrolled so as to output the content information to the informationreceiving apparatus, and a second mode in which the communication meansis controlled so as to output the content information with use of thecommunication band resource indicated by the resource information,characterized in that the control means selects the first mode if theinstruction signal does not contain the resource information, or thesecond mode if the instruction signal contains the resource information.

An information communication system according to the present inventioncomprises an information providing apparatus and an informationreceiving apparatus connected to a communication network, in which theinformation providing apparatus and the information receiving apparatusexchanges content information through communication with use of acommunication band resource of the communication network which isreserved prior to communication of the content information,characterized in that the information providing apparatus includesproviding communication means for making communication through thecommunication network, storage means for storing the contentinformation, and providing control means for controlling the providingcommunication means so as to output the content information, that theinformation receiving apparatus includes input means for inputting acommand based on an operation by a user, receiving communication meansfor making communication through the communication network, receivingcontrol means for controlling the receiving communication means so as tooutput an instruction signal based on the command inputted through theinput means, and display means for displaying the content informationreceived by the receiving communication means, and that if a switchinginstruction which indicates that second content information should bereceived in place of first content information is inputted as thecommand to the receiving communication means when the receivingcommunication means is receiving the first content information throughthe connection formed in the communication network, the receivingcontrol means makes control so as to output a disconnection instructionfor disconnecting the connection for transmitting the first contentinformation, which is formed in the communication network connecting thereceiving communication means and the information providing apparatus,and a formation instruction for forming the connection for transmittingthe second content information, which is formed in the communicationnetwork connecting the receiving communication means and the informationproviding apparatus.

The information providing apparatus in the information communicationsystem according to the present invention further includes detectionmeans for detecting whether or not resource information indicating thecommunication band resource is contained in an instruction signal, whenthe receiving communication means receives the instruction signal fromthe information receiving apparatus, and based on a detection resultfrom the detection means, the providing control means makes control soas to select a first mode in which a band reservation command forreserving the communication band resource is outputted and thecommunication means is controlled so as to output the contentinformation to the information receiving apparatus, if the instructionsignal does not contain the resource information, or a second mode inwhich the communication means is controlled so as to output the contentinformation with use of the communication band resource indicated by theresource information, if the instruction signal contains the resourceinformation.

Also, the information communication system according to the presentinvention further comprises a relay apparatus between the informationproviding apparatus and the information receiving apparatus,characterized in that the relay apparatus reserves the bandcommunication resource based on an instruction from the providingcontrol means and the receiving control means.

Also, the relay apparatus in the information communication systemaccording to the present invention reserves the communication resourceused for communication from the information providing apparatus to theinformation receiving apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing an example of the structure of a network ofclient terminals to which the present invention is applied.

FIG. 2 is a view showing an example of the structure inside a clientterminal.

FIG. 3 is a view showing an example of the structure inside a videoserver.

FIG. 4 is a display example of the screen of the client I/F.

FIG. 5 shows an example of data (resource reservation parameters) set ina client setting file.

FIG. 6 is a flowchart which explains an operation example of a clientterminal.

FIG. 7 is a view showing another display example of the screen of theclient I/F.

FIG. 8 is a flowchart which explains an operation example of a videoserver.

FIG. 9 is a view for explaining a state in which the receiver side isissuing a resource request message.

FIG. 10 is a view showing an example of the structure of ASP.

FIG. 11 is a view showing an example of the format of the ASP header.

FIG. 12 is a view showing an example of the structure of a backbonerouter.

FIG. 13 is a view showing an example of the structure of an edge router.

FIG. 14 is a view showing an example of the structure of a network.

FIG. 15 shows an ASP internal table.

FIG. 16 is a view showing the flow of an ASP message and explaining theprocedure until a VC is constructed in case where the receiver knowsQoS.

FIG. 17 is a view showing the flow of an ASP message and explaining theprocedure of extending a VC in case where only the sender knows QoS.

FIG. 18 is a view showing the flow of an ASP message and explaining theprocedure of extending a VC in case where the sender starts reservation.

FIG. 19 is a view explaining the procedure of performing bi-directionalcommunication in case where each of the sender and receiver knows QoS.

FIG. 20 is a view showing the flow of each ASP message and explainingthe procedure of extending a VC in the direction opposite to the flow incase where each of the sender and receiver knows QoS.

FIG. 21 is a view explaining the procedure of constructing a VC in casewhere the receiver knows QoS required for bi-directional communication.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, explanation will be made of preferred embodiments ofthe present invention with reference to the drawings.

FIG. 1 shows an example of a connection of a network of a clientterminal to which the present invention is applied.

Client terminals 11 and 12 are each comprised of a personal computerused by a member and are connected to a router through channels.Although only two terminals 11 and 12 are shown in the example shown inFIG. 1, this is merely an example and a plurality of terminals may beconnected to the router. In the following explanation, channels usingoptical fibers are cited as examples of channels connected to the clientterminals 11 and 12 (which will be called member lines). Also, in thefollowing explanation, a network called AMInet described later is usedas an example of the network connected to the channels using the opticalfibers. The client terminals 11 and 12 connected to an AMInet router 21of the AMInet 20 through member lines.

In this case, the AMInet is a network which is compatible as a host withthe Internet and is also a network architecture of a next generationwhich solves problems of existing network architectures. The AMInetarchitecture solves essential problems included in the Internetarchitecture, in view of the generation in which homes and enterpriseswill be always connected to an ultra-high-speed network of asymmetric/semi-symmetric type by realizing FTTH (T. Miki. Toward theService-Rich Era. IEEE Communications Magazine, Vol. 32, No. 2, February1994) and xDSL (G. T. Hawley. Systems Considerations for the Use of xDSLTechnology for Data Access. IEEE Communications Magazine, Vol. 35, No.3, March 1997).

That is, the AMInet architecture is characterized in realization ofdynamic construction of an optimum protocol stack, original high-speedresource reservation using IP, negotiation between equal classes ofdifferent nodes and between upper and lower classes in one same node,connection-oriented QoS guarantee, separation of an ID of a node and anaddress thereof, control between non-ends, an architecture independentfrom communication media, and the like. Note that the high-speedresource reservation protocol in the AMInet will now be called ASP(AMInet Set-up Protocol). The AMInet and ASP will be more specificallyexplained below.

The AMInet 20 is constructed by an AMInet router 21, an ATM network 22(which is merely an example and may be another network), and an AMInetrouter 23.

The AMInet router 21 forming part of the AMInet 20 is a router having anATM network interface which has original function expanded for theAMInet. This AMInet router 21 collects member lines and is connected tothe ATM network 22 as an example of a channel network. The ATM network22 is connected also to the AMInet router 23 in addition to the AMInetrouter 21. The AMInet router 23 is also a router having an ATM networkinterface which has original function expanded for the AMInet, like theAMInet router 21. In this example, the AMInet router 23 is connected toN pieces of servers through optical fibers. In FIG. 1, video servers32-1 to 32-N each of which is capable of providing video data and audiodata are cited as examples of N pieces of servers. In the following, thevideo servers 32-1 to 32-N will be represented simply by a video server32 unless the servers need to be distinguished from each other.

The video server 32 is, for example a video server capable compatiblewith Internet TV and Internet VoD, and can supply (or supply services ofproviding) at least video data and audio data to client terminals 11 and12.

FIG. 2 shows an example of an internal structure of the client terminal11.

An operating section 51 is constructed by a mouse or a keyboard, forexample, and is operated appropriately by a user when inputting apredetermined command to the control section 50. A display section 52 isconstructed by, for example, an LCD (Liquid Crystal Display), a CRT(Cathode Ray Tube), or another display device and displays variousinformation.

A communication section 53 is connected to the AMInet router 21 througha member line to make communication with the AMInet router 21. A database 54 stores a client interface (hereinafter abbreviated as I/F)program capable of responding to Internet TV and Internet VoD,predetermined data necessary for the client I/F, and an applicationprogram necessary for the communication section 53 to make communicationthrough the AMInet 20. Further, the database 54 appropriately storesdata provided through the AMInet 20. Note that the predetermined datarequired for the Internet TV and internet VoD will be resourcereservation parameters and the like which are required for reservingnetwork band resources when receiving providing services concerningvarious data such as video data, audio data, and the like from a server.These resource reservation parameters are distributed from the serverside and stored into the database 54 when a connection is made with aserver as a service provider, for example. In addition, the resourcereservation parameters can be previously supplied in form of any medium.In this case, resource reservation parameters picked up from thesupplied medium are stored into the database 54. Details of the resourcereservation parameters will be described later.

The control section 50 controls the operating section 51 to the database54 in accordance with the client I/F program and application programstored in the database 54, so as to execute various operations.

Note that the inside of the client terminal 12 is constructed to bebasically equal to the client terminal 11 and its illustration andexplanation will be omitted herefrom.

FIG. 3 shows an example of the structure of the video server 32-1.

A CPU 61 is arranged so as to execute various operations in accordancewith a program recorded in a ROM 62 or a hard disk 64. The RAM 63appropriately stores various data necessary for the CPU 61 to executevarious processing.

The hard disk 64 stores a server program for responding to predeterminedrequests transferred through the AMInet 20 and also stores a client I/Fprogram to be provided for a client terminal and data (e.g., resourcereservation parameters) necessary for the program. Further, the harddisk 64 is capable of storing data (e.g., video data and audio data) tobe provided as a service for a member (or client terminal).

Video data and audio data to be provided as service data for a clientterminal are supplied from the hard disk 64 or various devices connectedthrough the I/O section 66. The video data or audio data supplied fromthose various devices is transmitted directly from the communicationsection 65 to the AMInet 20 in response to the client terminal side oris once stored into the hard disk 64 from which the data is read inresponse to a request from the client terminal side and is transmittedfrom the communication section 65 to the AMInet 20.

The I/O section 66 is connected to, for example, an IEEE 1394 network67, and the IEEE 1394 network 67 is connected to, for example, a digitalVTR 68, a media converter 69, a television camera 70, a TV tuner 71, aradio tuner 72, and the like, as supply sources for supplying video dataand audio data to be provided as service data for a client terminal. Inaddition, the media converter 69 is connected to, for example, aplurality of analogue VTRs 73, 74, . . . This media converter 69converts analogue videos and audio signals, from the analogue VTRs, intodigital videos and audio data, and supplies the converted digital videsand audio data onto the IEEE 1394 network 67. That is, the data to besupplied from the server side to the client terminal side is not limitedto recorded video data but may be considered to be live video data beingcurrently picked up by the television camera 70, videos and audio dataprocessed through the media converter 69, and the like. Note that videodata to be transmitted may be, for example, in form of compressed imagedata according to the MPEG standard.

The communication section 65 is connected to the AMInet router 23through an optical fiber so as to make communication with the AMInetrouter 23.

The insides of the video servers 32-2 to 32-N are constructed to bebasically equal to the inside of the video server 32-1, and illustrationand explanation thereof will be omitted herefrom.

By the structure described above, a client terminal can receive servicesfor providing video data and audio data based on the Internet TV orInternet VoD from a video server. In the following, explanation will bemade of a processing procedure in case where a client terminal ofreceiving a service of providing video data and audio data through theInternet TV or Internet VoD from a video server.

FIG. 4 shows a display example of an initial screen of a client I/Ddisplayed as GUI (Graphical User Interface) on the screen of the displaysection 52 of the client terminal 11.

In the example of FIG. 4, program selection buttons 101-1 to 101-9indicating a plurality of program titles as contents to be provided byservices are arranged in the left side on the screen of the displaysection 52. Below the program selection button 101-9, an end button 102,a zapping button 103, 10 s setting button, and 20 s setting button 105are provided. A video display section 106 is positioned at the center inthe right side on the screen.

In this example, the client I/F is an example of I/F compatiblyresponding to the Internet TV and Internet VoD. In the case of FIG. 4,service names (program titles) which can be provided by the Internet VoDare indicated on the program selection buttons 101-1 to 101-8, and theprogram selection button 101-9 indicates a service name (program title)which can be provided by the Internet TV.

FIG. 5 shows examples of resource reservation parameters aspredetermined data necessary for the client I/F compatible with theInternet TV and Internet VoD. These resource reservation parameters arerequired for network resource reservation when receiving informationconcerning respective programs to be provided through the Internet TVand Internet VoD. For example, when a client terminal makes a connectionwith a server in the service providing side, the parameters aretransmitted from the server side and stored as a client setting file 54Ain the database 54 of the client terminal.

In the example of FIG. 5, set as resource reservation parameters are aservice number for specifying the content of a service, a program titlewhich can be provided as a service, a server address such as abroadcasting station address of Internet TV or Internet VoD (e.g., an IPaddress of a network layer), a port number which specifies a service ina server (e.g., a TCP/UDP port number of a transport layer), a transferrate for specifying a band resource required on a network when providinga service, a read/write size with respect to a socket as a unit of dataread/written from/into OS (operating system) by an application of aserve, a socket buffer size as the size of a buffer for a socket,maximum and minimum transfer sizes of data (in units of bytes)transferred on the network, a token packet size as one of parameters ina so-called token packet algorithm (e.g., the maximum data amount whichcan be outputted at once onto the network), and a multicast IP addressand port number which are used for executing multicast providing.

In case of Internet VoD, since one service (video data and audio data ofa program) is supplied for one client terminal, the service (video dataand audio data of a program) is supplied in form of uni-cast from aserver. Accordingly, in this case, the multicast IP-address/port-numberof the resource reservation parameters shown in FIG. 5 is neglected(e.g., set to 0/0). Also, in the Internet VoD, if provided video datais, for example, animation data and if the animation data matches withthe MPEG standard, a user (or client terminal) can select a desiredtransfer rate from several kinds of transfer rates such as 6M bps, 3Mbps, and the like, as the transfer rate for the animation data.

Meanwhile, in case of Internet TV, a plurality of client terminals existwith respect to one service (program), and therefore, the service(program) is provided in form of multicast from a server.

Returning to FIG. 4, program titles among resource reservationparameters are displayed on the program selection buttons 101.Accordingly, a user (or client terminal) selects a button displaying adesired program title from the program selection buttons 101 and canthen receives a service of video data and audio data corresponding tothe selected program through the Internet TV or Internet VoD.

The end button 102 is a button which is selected when a user terminatesa client I/F.

The zapping button 103 is operated by a user when the zapping mode isset on or off. If the zapping mode is set on, a plurality of videoscorresponding to the program selection buttons 101 are automatically andsequentially displayed on the image display section 106 for apredetermined time (e.g., 10 or 20 seconds in this example). In thismanner, the user can confirm videos of respective programs so that aninterested program can be found out with ease.

The 10 s setting button 104 is selected by a user when the display time(zapping time) for which respective programs are displayed automaticallyand sequentially is set to 10 seconds while the zapping mode is on. The20 s setting button 105 is selected by a user when the display time(zapping time) for which respective programs are displayed automaticallyand sequentially is set to 20 seconds while the zapping mode is on.

When an initial screen is displayed on the display section 52, i.e.,when the client I/F program is newly started, predetermined settings ofthe client I/F are initialized. For example, when the zapping mode isswitched on, the zapping time is initialized to either 10 or 20 seconds.

Next, FIG. 6 shows a processing procedure in the control section 50 ofthe client terminal 11 in case where a service of Internet TV orInternet VoD is received from a server.

In this FIG. 6, when the client I/F program is started in the step S40,the control section 50 controls the communication section 53 to makeconnection with a server and to receive and store data containingresource reservation parameters into the data base 54, for example, inthe step S41. Then, the initial screen of the client I/F shown in FIG. 4is displayed on the display section 52.

In a state in which the client I/F program is started and the initialscreen of the client I/F shown in FIG. 4 is displayed on the displaysection 52, the control section 50 waits in the step S1 until anycommand is inputted through the operating section. The control section50 goes to the processing of the step S2 and later if any command isinputted through the operating section 51 while waiting in the step S1.

In the step S2, the control section 50 determines whether or not acommand inputted through the operating section 51 in the step S1instructs end of the client I/F. The control section 50 executestermination processing of the client I/F program if it is determined bythe determination processing in the step S2 that an end command isinputted, i.e., if the operating section 51 is operated by a user toselect the end button 102.

The control section 50 goes to the processing of the step S3 if it isdetermined by the determination processing in the step S2 that a commandinputted through the operating section 51 does not instruct end of theclient I/D. The control section 50 determines whether or not the commandinputted through the operating section 51 is an operation commandconcerning the program selection buttons 101. If it is determined thatthe command is not an operation command concerning the program selectionbuttons 101, the control section 50 goes to the processing in the stepS4.

The control section 50 goes to the processing in the step S4 and thendetermines whether or not the command inputted through the operatingsection 51 in the step S1 is an operation command concerning the zappingbutton 103. If it is determined that the command is not an operationcommand concerning the zapping button 103, the control section 50 goesto the processing in the step S5. The control section 50 thus goes tothe processing in the step S5 and then determines whether or not thecommand inputted through the operating section 51 is an operationcommand concerning the 10s setting button 104 or the 20 s setting button105.

If the control section 50 determines that the command inputted throughthe operating section 51 in the step S1 is not an operation commandconcerning the 10s setting button 104 or the 20 s setting button 105,the control section 50 returns to the processing in the step S1 andwaits until a command is inputted from the operating section 51.Otherwise, in the processing in the step S5, if the control section 50determines that the command inputted through the operating section 51 inthe step S1 is an operation command which has selected either the 10 ssetting button 104 or the 20 s setting button 105, the control section50 goes to the processing in the step S6.

The control section 50 goes to the processing in the step S6 and thensets the zapping time to a time period corresponding to the 10 s settingbutton 104 or 20s setting button 105 selected in the step S5.Thereafter, the control section 50 returns to the processing in the stepS1 and waits until a command is newly inputted through the operatingsection 51.

Next, the control section 50 goes to the processing in the step S7 if itis determined in the determination processing in the step S3 that thecommand inputted through the operating section 51 is an operationcommand concerning the program selection buttons 101. In addition, ifthe control section 50 determines, in the determination processing inthe step S4, that the command inputted through the operating section 51is an operation command concerning the zapping button 103, the controlsection 50 switches ON the zapping mode as processing in the step S42and thereafter goes to the processing in the step S7.

The control section 50 prepares a message for requesting resourcereservation. This message is based on a high-speed resource reservationprotocol (ASP) described above, and is therefore called an ASP message.For example, when any one of the program selection buttons 101-1 to101-9 is operated in the step S1, the control section 50 reads resourcereservation parameters of a program corresponding to the operatedprogram selection button 101 from the data base 54, and interprets theparameters. The section 50 further determines an identification used forthe connection, e.g., VCI (Virtual Channel Identifier)/VPI (Virtual PathIdentifier), and prepares an ASP message for requesting resourcereservation together with the resource reservation parameter thereof. Inaddition, if the zapping button 103 is operated in the step S1 and ifthe zapping mode is switched on in the step S42, the control section 50reads resource reservation parameters of predetermined programs from thedata base 54, and interprets the parameters. The section 50 thendetermines VCI/VPI and prepares an ASP message (resource reservationrequest message) for requesting resource reservation together with theresource reservation parameter thereof.

If an ASP message for requesting resource reservation is generated inthe step S7, the control section 50 controls the communication section53 in the step S8, so as to transmit the ASP message to the AMInetrouter 21.

The ASP message for requesting resource reservation transmitted from thecommunication section 53 is transferred to the video server 32 which iscapable of providing a specified service among the video servers 32-1 to32-N.

It can be considered that there are ways of processing of resourcereservation for a network, i.e., resource reservation in the forwarddirection in which resource reservation is made in the same direction asthe transmission direction of the ASP message, and resource reservationin the backward direction in which resource reservation is made in thedirection opposite to the transmission direction of the ASP message.Details of the flow of the network resource reservation will bedescribed later. For example, in the process of transmitting an ASPmessage for requesting resource reservation to a video server 32 from aclient terminal 11, there is a case that resource reservation is made inthe direction opposite to the transmission direction of the ASP messageso that resource reservation is made firstly in the direction from theAMInet router 21 to the client terminal 11, next in the direction fromthe AMInet router 23 to the AMInet router 21, and then in the directionfrom the video server 32 to the AMInet router 23. There is another casethat, for example, the video server 32 receives a message for requestingresource reservation transmitted from a client terminal, and resourcereservation is made in the same direction (forward direction) as thetransimssion direction of the ASP message, in the process of returningan ASP message as a reply to the client terminal 11 from the videoserver 32, so that resource reservation is made firstly in the directionfrom the video server 32 to the AMInet router 23, next in the directionfrom the AMInet router 23 to the AMInet router 21, and then in thedirection from the AMInet 21 to the client terminal 11.

For example, in case where a client terminal 11 knows the amount ofresources of a network which are necessary for receiving service data(video data and audio data), a reservation method is adopted in whichresource reservation is a made in the direction opposite to thetransmission direction of the ASP message. For example, in case ofInternet VoD which practices uni-cast providing, the client terminal 11is previously notified of the amount of resources necessary for servicedata (video data and audio data), and the client terminal 11 reservesthe amount of resources necessary for receiving service data (video dataand audio data). Therefore, the resource reservation method in theopposite direction is adopted.

If the client terminal 11 does not know the amount of resources of thenetwork that are necessary for receiving service data (video data andaudio data), a reservation method is adopted in which resourcereservation is made in the same direction (forward direction) as thetransmission direction of the ASP message. For example, in case ofInternet TV which practices multicast providing, the client terminal 11is operated and a request of providing service data (video data andaudio data) is issued to the server 32. Then, the server 32 reserves theamount of resources necessary for providing the service data (video dataand audio data). Therefore, a resource reservation method in the samedirection (forward direction) is adopted.

After an ASP message for requesting resource reservation is transmittedin the step S8, the control section 50 determines whether or notresource reservation is successful in the step S9. That is, upon receiptof a message expressing that resource reservation has been successful orfailed as a result of resource reservation in the backward or forwarddirection, the control section 50 determines whether resourcereservation has been successful or failed. If it is determined in thestep S9 that resource reservation has been failed, the section 50controls the display section 52 so as to display the cause of thefailure of resource reservation, as processing in the step S10, and thenreturns to the processing in the step S1 thereby to advice a user tomake again the operation for selecting a program.

If it is determined in the step S9 that resource reservation has beensuccessful, the control section 50 controls the communication section53, as processing in the step S11, so as to receive service data (videodata and audio data of a program) transmitted from the video server 32.Next, the control section 50 goes to the processing in the step S12 andcontrols the display section 52 so as to display the video of thereceived service data on the video display section 106 of the clientI/F. In this manner, a video of a program corresponding to the programselection button 101-1, e.g., the video of “Baseball 1” is displayed onthe video display section 106, as shown in FIG. 7.

Next, in the step S43, the control section 50 determines whether or notthe zapping mode has been switched on. If it is determined in the stepS43 that the zapping mode has been switched on, the control section 50determines whether or not any command has been inputted from theoperating section S1, in the step S44. If it is determined no commandhas been inputted from the operating section 51, the control section 50determines whether or not a setting time of the zapping (zapping time)has elapsed, in the step S15. That is, if the 10 s setting button 104 isoperated in the step S6 and a zapping time of 10 seconds is set, thecontrol section 50 determines whether or not 10 seconds have passed.Otherwise, if the 20 s setting button 105 is operated in the step S6 anda zapping time of 20 seconds is set, the control section 50 determineswhether of not 20 seconds have passed. If the time of the initialsetting is set as the zapping time, the control section 50 determineswhether or not the time of the initial setting has passed.

Meanwhile, if it is determined in the step S15 that the set zapping timehas not elapsed, the control section 50 returns to the processing in thestep S11 and executes the processing from the step S11 to the step S15until the set zapping time elapses.

If it is determined in the step S15 that the set zapping time haselapsed, the control section 50 goes to the processing in the step S46.When the control section 50 thus enters into to the processing in thestep S46, the control section 50 generates an ASP message (resourcereservation release request message) for requesting release of thereservation, and controls the communication section 53 so as to transmitthe ASP message to the AMInet router 21. The ASP message for requestingrelease of the resource reservation contains information for specifyinga service to be terminated, e.g., information specifying a server,information specifying a client terminal, and the like.

The flow of the release processing of resource reservation on a networkadopts release of resource reservation only in the backward direction inwhich release of the resource reservation is carried out in thedirection opposite to the transmission direction of the ASP message,unlike the request for resource reservation. For example, in the processin which an ASP message for requesting release of resource reservationis transmitted from the client terminal 11 to the video server 32, theremay be a case that release of resource reservation is made in thedirection opposite to the transmission direction of the ASP message sothat the release is made firstly in the direction from the AMInet router21 to the client terminal 11, next in the direction from the AMInetrouter 23 to the AMInet router 21, and then in the direction from thevideo server 32 to the AMInet router 23.

After the ASP message for requesting releaser of resource reservation istransmitted in the step S46, the control section 50 makes control so asto receive a message expressing the result of the release of resourcereservation from the AMInet 21, and determines whether or not therelease of resource reservation has been successful. That is, uponreceipt of a message expressing success or failure of release ofresource reservation as a result of release of resource reservation inthe backward direction, the control section 50 determines whether or notthe releaser of resource reservation has been successful, depending onthe message. For example, if release of resource reservation has beenfailed due to a disconnection on the network or the like and a messageexpressing this failure is received, the control section 50 determinesthat the release of resource reservation has been failed, in the stepS47. Next, as processing in the step S18, the control section 50controls the display section 52 so as to display the reason for thefailure of the release of resource reservation or the like, and thenreturns to the processing in the step S1 to advise the user to makeoperation again for program selection or zapping.

Meanwhile, if it is determined in the step S47 that the releaser ofresource reservation has been successful, the control section 50executes setting of a channel (program) to be displayed next by zapping,as processing in the step S48. That is, at this time, the controlsection 50 sets a program next to the program presently displayed on thevideo display section 106 of the client I/F, e.g., a programcorresponding to the program selection button 101 in the lower stage.The control section 50 then returns to the processing in the step S7,and reads the resource reservation parameter corresponding to theprogram from the data base 54, thereby to prepare an ASP message forrequesting resource reservation. Subsequently, the processing from thestep S8 to the step S48 is executed with respect to the channel thusreset, so that the programs corresponding to the program selectionbuttons 101 are displayed sequentially on the video display section 106and zapping is thus carried out.

In addition, if it is determined in the step S43 that the zapping modehas not been switched on, the control section 50 goes to the processingin the step S13. The control section 50 thus goes to the processing inthe step S13, and then determines whether or not any command has beeninputted from the operating section 51. If it is determined that nocommand has been inputted from the operating section 51, the controlsection 50 returns to the step S11 and continues processing forreceiving service data, Meanwhile, if it is determined in the step S13that there has been any input from the operating section 51, the controlsection 50 goes to the processing in the step S16.

If it is determined in the step S13 that the command inputted throughthe operating section 51 is a command for changing the program displayedto the video display section 106 of the client I/F, i.e., if the useroperates the operating section 51 and selects a program selection button101 corresponding to another program, the control section 50 releasesthe resource currently reserved, as processing from the step S16.

That is, the control section 50 goes to the processing in the step S16and then generates an ASP message for requesting release of resourcereservation. Then, the control section 50 controls the communicationsection 53 so as to transmit the ASP message to the AMInet router 21.The ASP message for requesting release of the resource reservation atthis time contains information specifying a server, informationspecifying a client terminal, and information specifying a service to beended. Note that the flow of the processing of releasing resourcereservation on the network may be oriented in the backward direction andthe forward direction.

After an ASP message (resource reservation release request message) forrequesting release of resource reservation is transmitted in the stepS16, the control section determines whether or not the release ofresource reservation is successful, in the step S17. If it is determinedin the step S17 that the release of resource reservation has beenfailed, the control section 50 controls the display section 52 asprocessing in the step S18, so as to display the reason for the failureof the release of the resource reservation or the like, and then returnsto the processing in the step S1 thereby to advise the user to makeoperation again for selecting a program.

Meanwhile, if it is determined in the step S17 that the releaser ofresource reservation has been successful, the control section 50 returnsto the step S2. If it is determined in the step S2 that an end of theclient I/F has not been commanded, the control section 50 goes to thestep S7 through the step S3. In this step S7, the resource reservationparameter of the program newly selected (in the step S13) is read out.Subsequently, the control section 50 executes the processing from thestep S8, so that a video of another program is displayed on the videodisplay section 106. In the present embodiment, the control section 50can thus switches the program to be displayed on the video displaysection 106 of the client I/F.

In addition, if it is determined in the step S44 that any command hasbeen inputted from the operating section 51, the control sectiondetermines whether or not the 10 s setting button 104 or the 20 ssetting button 105 has been pressed, in the step S50. If it isdetermined in the step S50 that the 10 s setting button 104 or the 20ssetting button 105 has been pressed, a zapping time is set incorrespondence with the pressed setting button in the step S51, and thecontrol section 50 thereafter returns to the step S11. Otherwise, if itis determined in the step S50 that the 10 s setting button 104 or the 20s setting button 105 has not been pressed, the control section 50switches off the zapping mode, in the step S49, and thereafter goes tothe processing in the step S52. The control section 50 thus goes to thestep S52 and then determines whether or not the zapping button 103 hasbeen pressed. If the zapping button 103 has been pressed, the controlsection 50 goes to the step S11. Otherwise, if not pressed, the controlsection 50 goes to the processing in the step S16. In case where thecontrol section 50 thus goes to the processing in the step S16, the sameprocessing as described above is carried out.

From the above, the user can easily select, watch, and listen to aprogram without being conscious about reservation of a resource orrelease thereof, in the same manner as the user selects a channel of atelevision receiver set.

Next, FIG. 8 explains the processing procedure in the CPU 61 of a videoserver (e.g., a video server 32-1) which provides service data.

In a state in which the server program stored in the hard disk 64 hasbeen started, the CPU 61 waits until the communication section 65receives an ASP message from the client terminal 11 or 12, as processingin the step S21. Upon receipt of the ASP message, the CPU 61 goes to thestep S22.

The CPU 61 thus goes to the processing in the step S22 and thendetermines whether the received ASP message is a message for requestingresource reservation or a message for requesting release of resourcereservation. If it is determined that the message is for requestingresource reservation, the CPU 61 goes to the step S24.

There are two ways for resource reservation in the network, e.g.,resource reservation in the forward direction in which resourcereservation is made in the same direction as the transmission directionof the ASP message and resource reservation in the backward direction inwhich resource reservation is made in the direction opposite to thetransmission direction of the ASP message. When the processing goes tothe step S24, the CPU 61 of the video server 32 receives a messageexpressing that resource reservation has been successful or failed, fromeach AMInet router.

If it is determined in the step S24 that resource reservation has beensuccessful, the CPU 61 controls the communication section 65 so as totransmit a message expressing that resource reservation has beensuccessful, as processing in the step S25, and so as to transmit servicedata recorded in the hard disk 64 or data outputted from a deviceconnected to the I/O section 66, to the client terminal 11 or 12 throughthe AMInet 20, in the step S26. Thereafter, the CPU 61 returns to thestep S21.

Meanwhile, if it is determined in the step S24 that resource reservationhas been failed, the CPU 61 controls the communication section 65 so asto transmit a message expressing that resource reservation has beenfailed, to the client terminal 11 or 12 through the AMInet 20, asprocessing in the step S27. Thereafter, the CPU 61 returns to the stepS21.

In addition, if it is determined in the determination processing in thestep S22 that the received ASP message is a message for requestingrelease of resource reservation, the CPU 61 goes to the step S29.

Release of resource reservation in the network takes place only asrelease of resource reservation in the direction opposite to thedirection of the ASP message, as described above. The CPU 61 of thevideo server 32 goes to the processing in the step S29 and then receivesa message expressing that release of resource reservation has beensuccessful or failed from each AMInet router. Depending on the message,the CPU 61 determines whether or not release of resource reservation hasbeen successful.

If it is determined in the step S29 that release of resource reservationhas been successful, the CPU 61 controls the communication section 65 soas to transmit a message expressing that release of resource reservationhas been successful, to the client terminal 11 or 12 through the AMInet20, as processing in the step S30. Thereafter, the CPU 61 returns to thestep S21.

Otherwise, if it is determined in the step S29 that release of resourcereservation has been failed, the CPU 61 controls the communicationsection 65 so as to transmit a message expressing that release ofresource reservation has been failed, to the client terminal 11 or 12through the AMInet 20, as processing in the step S31. Thereafter, theCPU 61 returns to the step S21.

Next explanation will be made of realization of real-time communicationbased on integration of ATM and IP in the AMInet (ATM Control through IPfor Real-Time Communication in AMInet). This explanation deals with thebackbone as a prerequisite of the AMInet and the resource reservationprotocol ASP (AMInet Set-up Protocol) used in a wide area network whichconnects with homes. This technique is disclosed in the Japanese PatentApplication No. 9-279826 (filed on Sep. 26, 1997, by the same applicantsas in the present application, not opened on the priority data), andU.S. patent application Ser. No. 08/160,472 (filed on Sep. 24, 1998,granted to the same applicants as in the present application).

The ASP considers flexibility and applicability of IP and ATM as achannel-oriented data link, and integrates them thereby to realizehigh-speed flexible resource reservation. The ASP does not utilizesnormal signaling of ATM but constructs ATM VC (Virtual Channel) by usinga message transmitted by IP.

The ASP (AMInet Set-up Protocol) is a resource reservation protocolwhich operates in a wide area network and particularly in theenvironment constituted by routers based on the AMInet architecture. TheAMInet is constituted by routers each having an ATM switching function,which are backbone routers and edge routers provided between thebackbone routers. The resource to be reserved is a cue or the like whichis used during ATM VC processing or packet processing. Particularly inthe case of integration with ATM, the ASP does not utilize a normal ATMsignaling but a VC is constructed in a router having an ATM switch orATM function. Also, in the ASP, since IP is used to transmit a set-upmessage for resource reservation, high-speed resource reservation can berealized. Accordingly, the ATM switch does not use a VC of ATM calledSVC (Switched Virtual Channel) at all, but a VC is dynamicallyconstructed by a message using IP. Note that this kind of VC is called aPVC (Permanent VC)-on-demand. This PVC-on-demand can dynamicallyestablish or disconnect a VC in a form different from a normal SVC byusing ASP.

Even in case of using the ASP, data is transmitted by normal IP.Therefore, an IP packet is mapped on a specific reserved resource.Accordingly, the ASP can easily respond widely to applications whichhave been conventionally used and also new applications which will bereleased in the future. This mapping is achieved by comparing sourceswith destination IP addresses, sources with destination port numbers andprotocol identification fields. Normal IP traffic, i.e., best efforttraffic (BE) is transferred through a default BE VC. Resources reservedby using the ASP are not influenced by the BE traffic. In addition, aflow gathered into one VC in view of saving resources can coexistwithout being influenced by the BE traffic.

Next, a flexible set-up mechanism will be explained. In the ASP,resources can be reserved in various forms to use resources efficientlyor to make resource reservation which matches with a request from anapplication. That is, in the Internet or ATM environment, there arevarious kinds of applications including application of broadcasting typeand applications of conversation type in which data is transmitted inboth directions, such as television meeting, remote diagnosis,video-on-demand (VoD), a multicast application using Mbone, and thelike. According to the ASP, QoS parameters can be efficiently mappedscalably onto resource reservation parameters in the lowermost layer, inany cases.

For example, in the case of VoD, since data always flows from a servertoward a client terminal, a VC needs not be constructed in twointeractive directions. That is, in case of using ASP, exchanges ofmessages inherent to ASP, exchanges of controls other than datatransmissions necessary for applications (e.g., a request or so forchanging a video to be watched from a client terminal side), andexchanges necessary for upper layers (e.g., a transport layer and thelike) can be realized only by using a default BE VC or anotherspecialized VC. ASP messages are transmitted through a default BE VC ora specified special VC.

Meanwhile, a TV meeting application of conversation type requires abi-directional VC, and the ASP responds to a bi-directional VC like thisconversation type application. Further, a conversation type applicationsupports an asymmetrical model in which different pieces of QoS arerespectively set for the upstream and downstream traffics.

Also, in the ASP, a resource reservation request can be issued from thereceiver side and also from the transmitter side, like in the case ofRSVP or ST-2+ (Stream Transport Protocol-2+). That is, depending on theapplication or the environment, the QoS information required whenreserving a resource is possessed by the transmitter side in some casesand by the receiver side in the other cases. In any cases, the ASP canset so as to perform all reservations through one bus. Further, the ASPcan have a response message which notifies that reservation has beencompleted upon necessity.

FIG. 9 shows an example in which a message for requesting resourcereservation is issued as an ASP message by the receiver side.

This shows a case where a broadcasting type application for a videoutilizes the ASP. That is, data is transmitted only in the directionfrom a server (hereinafter called a sender) 1 as a transmitter side to aclient terminal (hereinafter called a receiver) 7. Among the routers 2to 6 in the figure, the routers 2 and 6 are edge routers, and therouters 3, 4, and 5 are backbone routers.

In the receiver 7, at first, QoS parameters are interpreted thereby todetermine VPI/VCI used in this connection, and an ATM NIC (NetworkInterface Card) is set if necessary. Also, the receiver 7 prepares anASP message (resource reservation request message) containing thisinformation and transmits this ASP message toward the edge router 6adjacent to the backbone (backbone router 5). This ASP message istransmitted by IP, and processed every time IP is hopped. In the case ofthe example shown in FIG. 9, when a message reaches the edge router 6,the edge router 6 sets VPI/VCI parameters toward the receiver 7. TheVPI/VCI is individually managed in each node. Thus, the ASP message istransferred in the upstream direction toward the sender 1. In each ofthe routers 2 to 6, a VC is set in the direction opposite to thedirection in which the ASP message is transmitted (resource reservationin the backward direction). Although not shown in the figure, when anASP message is transmitted to the sender 1 and reservation issubstantially completed, a reply message is transmitted from the sender1 to the receiver 7. At this time point, a VC is constructed from thesender 1 toward the receiver 7 at least in the backbone router. That is,in the structure shown in FIG. 3, IP is cut through during data transferby using the VC, so that communication can be made by only the ATM.

FIG. 9 shows only one form of flexible set-up in the ASP. For example,in case where only the sender 1 has QoS information and a resourcereservation request is issued from the receiver 7 by a multicastapplication, a message can be prepared such that setting of a VC iscarried out at the second path the reply message in the above example isreturned. Further, it is possible to construct a bi-directional VC withonly the first path.

Next, in the ASP, since an ATM VC is constructed by its original set-upmechanism, it is unnecessary to prepare previously another VC and QoS ofa resource already reserved can be dynamically changed. In addition, theapplication can upgrades the service level. For example, in case whereBE is simply shifted to integrated services (IS), the data flow can beremapped onto a new VC as shown in FIG. 9 from a default BE VC.

Next explanation will be made of integration with QoS routing. In theASP, supports for selecting a route have been considered when setting upa VC. Specifically, when reserving a resource, a routing table in theconventional IP level is not used but route information is supplied froma module which manages an original routing table for a flow requiringIS. In this manner, in the ASP, a different route can be used for everyflow in match with the QoS request and the situation of usableresources.

In addition, conventional resource reservation protocols and routingmechanisms have been considered respectively on the basis ofprerequisites independent from each other. However, the ASP realizesintegration with QoS routing. This is carried out by feeding backresource reservation information held by the ASP to the module of theQoS routing. Therefore, in the ASP, selection of a substitutive route iseasy when reservation is failed, and the entire network can beefficiently utilized without concentrating resource reservation onto oneroute.

Next, the ASP is equipped, for example, as demon process (aspd) of UNIX,in the user space. A prototype is now operating at FreeBSD 2.2.1, and isintegrated with libraries (swctl lib) for controlling the ATM switch anda module (afmap) for setting ATM NIC (see FIG. 10). At present, threetypes of routers are supported and the home router has interfaces for100Base-T Ethernet and ATM. The edge router is realized as a routerhaving a plurality of ATM interfaces. The backbone router is constructedby a PC including an ATM switch and an IP engine for controlling the ATMswitch. The presently existing prototype uses ATM interface cards forPCI bus and a Fore ASX-200WG ATM switch, manufactured by Adaptec andEfficient Networks. ASP messages are equipped with use of raw IP.

The backbone router uses switch control libraries described above inorder to set PVC-on-demand by the equipped switch. The IP flow whichrequires IS is mapped to a VC of CBR (Constant Bit Rate). In addition,at present, the ASP respond to multicast by creating a one-to-manymulticast VC. Further, the ASP supports join and resource reservation bya leaf.

In consideration of scalability of ATM resources starting fromidentifications such as VCI and the like, the IP flow is mapped onto aVC in units of applications with only a low efficiency. However, in thiscase, the flow can be dynamically gathered into a VC by using the ASP.

The above description has been made of resource reservation protocol ASPin the AMInet. The ASP has introduced its original set-up mechanism andintegrates the flexibility of IP and the QoS guarantee by a VC.Accordingly, the AMInet realizes dynamic QoS changes, integration withQoS routing, and flexible set-up, so that high-speed set-up can berealized by equipping a prototype.

Next, explanation will be made of the details of the ASP (AMInet Set-upProtocol) as a protocol for carrying out resource reservation in theAMInet. In this case, the term of “set-up” means that status/informationis set for resource reservation in a receiver and a sender or a routeron the way of the route when resource reservation is carried out.

By the ASP, a VC having a channel exchange function in a lower layer orassignments of cues (e.g., class of CBQ (Class Based Queueing) and thelike) which the packet scheduler can provide are expressed in abstractas resources, and correspondences are assigned such that data flowingthrough an IP network is transferred without influencing other data. Asa specific example, the ASP carries out abstract expression as resourceswhich are controlled by the VC of ATM and UPC (Usage Parameter Control),and the resources are reserved. The VC is let correspond to the flow ofIP. Here, the terra of “flow” expresses the information as follows. Theinformation are a protocol as a protocol identifier, a destination IPaddress as an IP address of a receiver, a source IP address as an IPaddress of a sender, a destination port address of a receiver, and asource port address of a sender.

The set-up of the ASP, i.e., exchange of a protocol message of the ASPis equipped on the IP. Therefore, in case of preparing a VC of ATM orthe like on demand, it is unnecessary to use the signaling mechanismactually prepared by the ATM, and this limitation is avoided so thatflexible and efficient resource reservation can be achieved.

In addition, the ASP has functions which are mainly the same as those ofRS VP and ST-2 and flexibly respond to the VC of the ATM, therebyeffecting the following functions. That is, reservation of resources canbe achieved both under the control by the receiver side and under thecontrol by the sender side, both in a hard state and a soft state.Flexible set-up can be achieved in consideration of the VC of the ATM,and assignments of bands (resources) specialized for protocol control(reservation control) can be achieved.

FIG. 11 shows an example of the format of a header of the ASP. Set inthe field of flags in FIG. 11 is information indicating that thedirection in which a resource is reserved is one single direction or twointeractive directions. Set in the prev_hop field is information formaking massages pass through one same route in case where exchange ofmessages reciprocally carried out between a receiver and a sender. VPI(Virtual Path Identifier) is set in the next VPI field, and VCI (VirtualChannel Identifier) is set in the VCI field.

In the next field, information of the above flow (flowinfo) is set. Thisflow information includes, for example, length, address family,reserved, protocol as a protocol identifier, destination IP address asan IP address of a receiver, a source IP address as an IP address of asender, a destination port address of a receiver, and a source portaddress of a sender.

Thereafter, the flow specification of the sender (s_flowspec) and theflow specification of the receiver (r_flowspec) are set. The flowspecification of the sender (s_flowspec) indicates QoS necessary fordata which the sender sends, while the flow specification of thereceiver (r_flowspec) indicates QoS necessary for data which thereceiver sends. In the presently existing prototype, only the peak cellrate for setting a CBR (Constant Bit Rate) service of the ATM isincluded in each flowspec field.

Routers in the form equipped with the ASP are mainly classified into abackbone router as shown in FIG. 12, an edge router as shown in FIG. 13,and a home router. In addition, it is necessary for the end host toexchange ASP messages.

The backbone router 14 is an intermediate node for constructing a largescale network and the substance thereof is constructed by a softwareengine (IP engine) 15, and a switch section (e.g., ATM SW) (switchingengine) 16 which provides a VC mechanism. That is, in this case, thebackbone routers are connected to each other thereby constructing an IPnetwork. However, cut-through is enabled by setting a VC.

An edge router 81 is provided at an entrance/exit of a net formed by aplurality of backbone routers. There is a possibility that anothernetwork or another router is connected in the side opposite to thebackbone. The edge router 81 has a protocol stack of a normal IP, andone or more ATM interfaces 82 to 84.

FIG. 14 shows an example of connection of the entire network. As shownin this figure, servers (senders) 91 and 97 may be connected directly tothe backbone 92 consisting of a plurality of backbone routers 14.However, normal end nodes 94 to 96 are connected to the backbone 92through the edge router 93. Also, another router can be set at the topof the edge router 93. The end node (receiver) 94 is connected to theedge router 93 through the ATM interface 94a. The end node (receiver) 95is connected to the edge router 93 through the ATM interface 95a. Theend node (receiver) 96 is connected to the edge router 96 through theATM interface 96a.

In this case, resources reserved by the routers and the method ofreservation thereof are important for the ASP. It is necessary for thebackbone router to set a VC in the switch.

Also, the backbone router 92 needs to map a specified flow to a newlyprepared VC (resource) at the entrance through which data flows into thebackbone. Mapping to the VC is carried out by an edge router. In casewhere a server is directly connected to the backbone, the ATM interfaceto the backbone of the node needs to carry out mapping onto the VC.

A status table for managing a reservation situation of resources asshown in FIG. 15 is maintained in the ASP module of each node.

This table manages information of the VC for input and information ofthe VC for output and makes correspondences between the VC and the flowinformation (flowinfo). In addition, since information concerningnetwork interfaces for input and output is required in case of an edgerouter, a field for the information is provided. In this case, the portsection of corresponding VC information is not used.

To make normal communication such as communication by IP, the VC of theATM needs to be prepared in two interactive directions. However, the VCcan be constructed flexibly by using the ASP.

Some applications require communication in one single direction andother applications require communication interactively in twodirections. For example, in case of an application in the form of VoD(Video on Demand), communication to a server may take place when areceiver issues a request for an image, although a video data flows onlyin one single direction from a server (sender) to a client terminal(receiver). That is, in this case, for example, resource reservationmessages are exchanged through a specialized VC by making a request tothe ASP. The other necessary exchanges flow through a default data VC(e.g., a normal route of IP). Accordingly, in this case, an applicationwhich requests a resource to the ASP needs only to form a VC only in onesingle direction by specifying the single direction communication, andtherefore, the identification and band width can be saved. Also, in caseof multicast in the broadcasting side, resource reservation can besufficiently realized by this reservation method.

However, in case of a conversation type application such as videoconference or the like, data flows bi-directionally. The necessity thatdata must flow bi-directionally is common to normal communication.However, in case of using the ASP, the application can set different QoSfor data of each direction. Setting of QoS with respect to the flows ofdata in two interactive directions is performed on the basis of thevalues (s_flowspec and r_flowspec) in two flow spec fields (flowspecs).In case where a null (NULL) value is contained in any flow spec field,reservation of the VC in its direction is not carried out.

FIG. 16 shows the procedure in which a VC in one single direction isconstructed in case where the receiver 47 knows QoS. Note that therouters 42 and 46 are edge routers, and the routers 43, 44, and 45 arebackbone routers. That is, the receiver 47 sets, for example, a value of0 which indicates that the direction in which a VC is constructed is onesingle direction, in the flag (flags) field of the ASP header, and setsinformation expressing the band width of the VC (e.g., 5M bps(Mega-bit/second)) in the flowspec (s_flowspec) of the sender of the ASPsender. The receiver 47 then transmits them to the sender 41. As amessage of the ASP flows from the receiver 47 to the sender 41, eachrouter constructs a VC in the direction opposite to the direction inwhich the ASP message flows.

At first, the edge router 46 constructs a VC in the direction oppositeto the direction in which the ASP message flows. Likewise, the VC isconstructed by the backbone routers 45, 44, and 43 and the edge router42 each in the direction in which the ASP message flows.

At this time, in each switching engine SW which constructs the backbonerouters 43 to 45, a predetermined input port and a predetermined outputport are connected to each other and the VC is constructed.

FIG. 17 shows the procedure through which the VC is constructed in casewhere only the sender knows QoS.

At first, the receiver 47 transmits, to the sender 41, an ASP message inwhich a null (NULL) value is set in the flowspec (s_flowspec) field ofthe sender in the ASP header, and requests construction of a VC. Uponreceipt of this ASP message, the sender 41 interprets this message andsends, by return, an ASP message in which a value corresponding to apredetermined band width is set in the flowspec (s_flowspec) field ofthe sender in the ASP header. Each router constructs a VC in the samedirection as the direction in which this ASP message flows. That is, theVC is constructed in the same direction as the direction in which theASP message flows each by the edge router 42, the backbone routers 43,44, and 45, and the edge router 46.

FIG. 18 shows a procedure in which a VC is extended in case where thesender 41 starts reservation. In this case, an ASP message flows in onesingle direction, and routers construct a VC. That is, the sender 41transmits an ASP message in which a value corresponding to apredetermined band width is set in the flowspec (s_flowspec) field ofthe sender in the ASP header.

Based on this ASP message, the edge router 42 constructs a VC in thesame direction as the direction in which the ASP message flows, atfirst. Next, the VC is constructed in the order of the backbone routers43, 44, and 45 and the edge router 46.

In many cases, the sender cannot send data before the sender confinesthat reservation has been completed. Thereafter, an ASP message forconfirmation is sent from the receiver 47 to the sender 41, although notshown in the figure.

FIG. 19 shows a procedure in which bi-directional communication iscarried out in case where each of the sender and the receiver knows theQoS which is required when transmitting data. In this case, when an ASPmessage (resource reservation request message) flows in each direction,a VC is extended in each direction.

That is, the sender 41 transmits, to the receiver 47, an ASP message inwhich a value corresponding to the band width of the VC in thedownstream direction (e.g., the direction from the sender 41 to thereceiver 47) is set in the flowspec (s_flowspec) field of the sender inthe ASP header. In this manner, a VC in the downstream direction whichis the same as the direction in which the ASP message flows isconstructed by the edge router 42, the backbone routers 43, 44, and 45,and the edge router 46, in this order.

Meanwhile, the receiver 47 transmits, to the sender 41, an ASP messagein which a value corresponding to the band width of the VC in theupstream direction (e.g., the direction from the receiver 47 to thesender 41) is set in the flowspec (r_flowspec) field of the receiver inthe ASP header. In this manner, a VC in the upstream direction which isthe same as the direction in which the ASP message flows is constructedby the edge router 46, the backbone routers 45, 44, and 43, and the edgerouter 42, in this order.

Also, as shown in FIG. 20, in case where each of the sender and receiverknows QoS which is required when receiving data, an ASP message(resource reservation request message) flows in each direction, andthen, a VC is extended in the direction opposite to the direction inwhich each message flows, on the contrary to the case shown in FIG. 19.

That is, the sender 41 transmits, to the receiver 47, an ASP message inwhich a value corresponding to the band width of the VC in the upstreamdirection (e.g., the direction from the receiver 47 to the sender 41) isset in the flowspec (r_flowspec) field of the receiver in the ASPheader. In this manner, a VC in the upstream direction which is oppositeto the direction in which the ASP message flows is constructed by theedge router 42, the backbone routers 43, 44, and 45, and the edge router46, in this order.

Meanwhile, the receiver 47 transmits, to the sender 41, an ASP messagein which a value corresponding to the band width of the VC in thedownstream direction (e.g., the direction from the sender 41 to thereceiver 47) is set in the flowspec (s_flowspec) field of the sender inthe ASP header. In this manner, a VC in the downstream direction whichis opposite to the direction in which the ASP message flows isconstructed by the edge router 46, the backbone routers 45, 44, and 43,and the edge router 42, in this order.

FIG. 21 shows the procedure in which a VC is constructed in case wherethe receiver knows QoS required for bi-directional communication. Inthis case, the bi-directional VC is prepared by one resource reservationrequest message.

That is, the receiver 47 sets, for example, a value of 1 which indicatesthat a VC is to be constructed bi-directionally, in the flag (flags)field in the ASP header. Further, the receiver 47 sets a valuecorresponding to the band width of the VC in the downstream direction,in the flowspec (s_flowspec) field of the sender in the ASP header, andalso sets a value corresponding to the band width of the VC in theupstream direction, in the flowspec (r_flowspec) field of the receiver.Then, the receiver 47 sends the ASP message containing the ASP header tothe sender 41. In this manner, at first, in the edge router 46, a VC inthe upstream direction with a band width set in the flowspec(r_flowspec) of the receiver and a VC in the downstream direction with aband width set in the flowspec (s_flowspec) field of the sender areconstructed. Next, in the backbone routers 45, 44, and 43, and the edgerouter 42, a VC in the upstream direction with a band width set in theflowspec (r_flowspec) field and a VC in the downstream direction with aband width set in the flowspec (s_flowspec) field of the sender arerespectively constructed.

Thus, the ASP can construct a VC in various methods, and a selectionamong these methods can be made from an upper layer. It is thereforepossible to realize set-up suitable for applications.

The above explanation has been made with respect the ASP whichintegrates ATM and IP and sets up a VC on demand without using ATMsignaling.

In addition to the above, explanation will now be made of a mechanismfor dynamically changing the relationship between the VC (resource) andthe flow with use of the function of the ASP. At present, data withrespect to a VC sinks from an edge router to a receiver, i.e., the datacuts through. Therefore, data with respct to a VC passes through theswitches of a plurality of backbone routers, and directly passes througha VC of ATM to the edge router in the receiver side.

Taken into consideration that the data sinks at the edge router, if anASP message is issued so as to effect feed-back thereon, it is possibleto shift an existing communication using another VC can be shifted to aVC which has already been prepared. That is, during communication, theVC can be changed and the intermediate route or the like can bedynamically changed, at the entrance to the backbone.

In the following, explanation will be made of advantages obtained byassembling this mechanism into the ASP. This mechanism is not limited tothe ASP but can be effectively used when linked with RSVP or the like.

For example, in case of ATM signaling, it is difficult to change theroute after set-up of the VC is once completed. This is because the VCmust be extended in the manner of end-to-end. Meanwhile, the RSVP hasadvantages in that it is robust and is applicable to the environment. Atlast, according to the presently existing IP routing, the route ischanged, and therefore, the RSVP is not suitable for real-timecommunication. In order to solve this problem, the RSVP introduces routepinning so that setting can be made so as not to permit a change basedon routing, with respect to a clearly reserved route.

By adopting this method, the route can be easily changed even ifcommunication continues. Although a route is not changed in normalcases, a change of a route can be easily permitted by introducing QoSrouting.

Also, according to this method, the flow received just duringcommunication can be collected into a predetermined VC, so thatresources such as VCI and the like can be saved.

Further, according to this method, reservations for a certainorganization, application, or the like can be collected.

Also, according to this method, a plurality of communication routes canbe prepared for a predetermined destination, and route/resource ofanother session can be collected in case where communication such as anew session or the like requires a certain amount of resource capacity.

In addition, according to this method, the resource reservation statusof a session during communication can be dynamically changed.

Although attention is here particularly paid to an edge router, thismechanism can be realized in a backbone router. As an equipment, afterpreparation is made for remapping the flow to which attention is paid,this switching is carried out at a high speed by the edge router.Although equivalent operation can be made with use of a backbone router,it is difficult to collect information required therefor, and besides,it is undesirable to complicate the function of the backbone routeritself by providing this kind of mechanism.

In case of an edge router, the number of terminals or home routerscollected in the end side can be grasped to some extent, and therefore,suitable routing corresponding to the number can be performed, so thatcollection of information is more limited and simplified than a backbonerouter.

In this method, it should be noted that the flowing data is influencedby operation of the edge. At first, there is a possibility that loss maybe caused in the data to be transmitted by switching the VC in thesender side.

Also, at the edge in the receiver side, data is transmitted temporarilyfrom two VCs, so that the receiver side might receive reiteratively thedata.

In this respect, to guarantee the correctness of data, it is desirableto use a transport protocol having high reliability.

Although explanation has been made with respect to the case of reservinga VC in the embodiment described above, the present invention can beapplied to the case of reserving another resource such as UPC (UsageParameter Control) or the like.

In this example, a server or a client terminal are specified bycombining the IP address with the socket port number. However, anotherdifferent method can be used.

As a medium for providing a computer program for executing processing asdescribed above, it is possible to use a communication medium such as anetwork, a satellite, or the like, in addition to a recording mediumsuch as a magnetic disk, a CD-ROM, a solid memory, or the like.

According to the information receiving apparatus and method, theinformation providing apparatus, and the information communicationsystem of the present invention, processing necessary for resourcereservation and releaser of the resource reservation is carried out whena service is selected. Therefore, a user can carry out reservation of aresource or release thereof without consciousness.

1. An information receiving apparatus which is connected to aninformation providing apparatus by forming a connection in acommunication network and which receives content information from theinformation providing apparatus through the connection, comprising:input means for inputting a command based on an operation by a user;communication means for making communication through the communicationnetwork; control means for controlling the communication means so as tooutput an instruction signal, based on the command inputted through theinput means; and display means for displaying the content informationreceived by the communication means, characterized in that if aswitching instruction which indicates that second content informationshould be received in place of first content information is inputted asthe command to the communication means when the communication means isreceiving the first content information through the connection formed inthe communication network, the control means makes control so as tooutput a disconnection instruction for disconnecting the connection fortransmitting the first content information, which is formed in thecommunication network connecting the communication means and theinformation providing apparatus, and a formation instruction for formingthe connection for transmitting the second content information, which isformed in the communication network connecting the communication meansand the information providing apparatus, further characterized in thatprior to formation of the connection, the control means controls makescontrol such that the communication means outputs a reservationinstruction signal for making reservation of a communication bandresource of the communication network, as the instruction signal, andfurther characterized in that if the control means recognizes thecommunication band resource which is necessary for the contentinformation to be received, the control means makes control such thatthe communication means outputs the reservation instruction signalcontaining resource information indicating the communication bandresource, or if the control means does not recognize the communicationband resource which is necessary for the content information to bereceived, the control means makes control such that the communicationmeans outputs the reservation instruction signal without containing theresource information indicating the communication band resource.
 2. Anapparatus according to claim 1, further comprising storage means forstoring predetermined resource information used for reserving acommunication band resource necessary for transmitting the contentinformation, characterized in that the control means generates theformation instruction containing the predetermined resource informationstored in the storage means, when forming the connection.
 3. Anapparatus according to claim 2, characterized in that the storage meansstores information used for reserving a communication band resource fortransmitting the content information as the predetermined resourceinformation.
 4. An information receiving apparatus which is connected toan information providing apparatus by forming a connection in acommunication network and which receives content information from theinformation providing apparatus through the connection, comprising:input means for inputting a command based on an operation by a user;communication means for making communication through the communicationnetwork; control means for controlling the communication means so as tooutput an instruction signal, based on the command inputted through theinput means; and display means for displaying the content informationreceived by the communication means, characterized in that if aswitching instruction which indicates that second content informationshould be received in place of first content information is inputted asthe command to the communication means when the communication means isreceiving the first content information through the connection formed inthe communication network, the control means makes control so as tooutput a disconnection instruction for disconnecting the connection fortransmitting the first content information, which is formed in thecommunication network connecting the communication means and theinformation providing apparatus, and a formation instruction for formingthe connection for transmitting the second content information, which isformed in the communication network connecting the communication meansand the information providing apparatus, further characterized in thatafter outputting the disconnection instruction for instructingdisconnection of the connection for content information presentlyreceived at a previously set time interval, the control means makescontrol so as to output the information instruction for instructingformation of the connection for transmitting content informationaccording to a previously set order.
 5. An information receiving methodin which a connection is made in a communication network to aninformation providing apparatus and content information is received fromthe information providing apparatus through the connection, comprising:A method for communications on a network between an informationproviding apparatus and a content receiving apparatus, the methodcomprising: an input step of inputting a command to the contentreceiving apparatus based on an operation by a user; a communicationstep of making communicationcommunicating a signal as a result of thecommand through thea communication network and receiving content datafrom the information providing apparatus at the content receivingapparatus over the communications network; a control step of controllingthe communication step content receiving apparatus so as to output aninstruction signal, based on the inputted command inputted through theinput step ; and a display step of displaying the content informationreceived through the communication step communications network,characterized in that if a switching command which instructs that secondcontent information should be received in place of first contentinformation is inputted as the command in the communication step , basedon only one operation by a user in the input step , when the firstcontent information is being received in the communication step throughthe connection formed in the communication network, the control stepmakes control so as to output the content receiving apparatus iscontrolled to output a disconnection instruction for instructingdisconnection of the connection for transmitting the first contentinformation, which if formed in the communication network connected withthe information providing apparatus by the communication step , and aformation instruction for instructing formation of the connection fortransmitting the second content information, which is formed in thecommunication network connected with the information providing apparatusin the communication step , further characterized in that prior toformation of the connection, the control step makes control such that areservation instruction signal for making reservation of a communicationband resource of the communication network is outputted as theinstruction signal in the communication step , and further characterizedin that if the communication band resource which is necessary for thecontent information to be received is recognized in the control step,the control step makes control such that the a reservation instructionsignal containing resource information indicating the communication bandresource is outputted in the communication step by the content receivingapparatus, or if the communication band resource which is necessary forthe content information to be received is not recognized in the controlstep, the control step makes control such that the a reservationinstruction signal without containing resource information indicatingthe communication band resource is outputted in the communication stepby the content receiving apparatus.
 6. A method according to claim 5,further comprising a storage step of storing predetermined resourceinformation used for reserving a communication band resource necessaryfor transmitting the content information, characterized in that thecontrol step generates the a formation instruction containing thepredetermined resource information stored in the storage step, isgenerated when forming the connection.
 7. A method according to claim 56, characterized in that information used for reserving a communicationband resource for transmitting the content information is stored as thepredetermined resource information in the storage step .
 8. Aninformation receiving method in which a connection is made in acommunication network to between a content receiving apparatus and aninformation providing apparatus and content information is received fromthe information providing apparatus through the connection, comprising:an input step of inputting a command to the content receiving apparatusbased on an operation by a user; a communication step of makingcommunicationcommunicating a signal as a result of the command throughthea communication network and receiving content data from theinformation providing apparatus at the content receiving apparatus overthe communications network; a control step of controlling thecommunication step content receiving apparatus so as to output aninstruction signal, based on the inputted command inputted through theinput step ; and a display step of displaying the content informationreceived through the communication step from the information providingappartus, characterized in that if a switching command which instructsthat second content information should be received in place of firstcontent information is inputted as the command in the communication step, based on only one operation by a user in the input step, when thefirst content information is being received in the communication stepthrough the connection formed in the communication network, the controlstep makes control so as to output the content receiving apparatusoutputs a disconnection instruction for instructing disconnection of theconnection for transmitting the first content information, which ifformed in the communication network connected with the informationproviding apparatus by the communication step , and a formationinstruction for instructing formation of the connection for transmittingthe second content information, which is formed in the communicationnetwork connected with the information providing apparatus in thecommunication step , further characterized in that after outputting thedisconnection instruction for instructing disconnection of theconnection for content information presently received, at a previouslyset time interval, the control step makes control so as to output thecontent receiving apparatus outputs the formation instruction forinstructing formation of the connection for transmitting contentinformation according to a previously set order.
 9. An informationproviding apparatus which is connected to an information receivingapparatus through a communication network and which provides theinformation receiving apparatus with content information, with use of acommunication band resource of the communication network which isreserved prior to providing of the content information, comprising:communication means for making communication through the communicationnetwork; storage means for storing the content information;directiondetection means for detecting whether or not resourceinformation indicating the communication band resource is contained inan instruction signal, when the communication means receives theinstruction signal from the information receiving apparatus; and controlmeans for outputting a band reservation command for reserving thecommunication band resource, based on a detection result from thedetection means, and for making control to make a selection from a firstmode in which the communication means is controlled so as to output thecontent information to the information receiving apparatus, and a secondmode in which the communication means is controlled so as to output thecontent information with use of the communication band resourceindicated by the resource information, characterized in that the controlmeans selects the first mode if the instruction signal does not containthe resource information, or the second mode if the instruction signalcontains the resource information.
 10. An information communicationsystem comprising an information providing apparatus and an informationreceiving apparatus connected to a communication network, in which theinformation providing apparatus and the information receiving apparatusexchanges content information through communication with use of acommunication band resource of the communication network which isreserved prior to communication of the content information,characterized in that the information providing apparatus includesproviding communication means for making communication through thecommunication network, storage means for storing the contentinformation, and providing control means for controlling the providingcommunication means so as to output the content information, theinformation receiving apparatus includes input means for inputting acommand based on an operation by a user, receiving communication meansfor making communication through the communication network, receivingcontrol means for controlling the receiving communication means so as tooutput an instruction signal based on the command inputted through theinput means, and display means for displaying the content informationreceived by the communication means, and if a switching instructionwhich indicates that second content information should be received inplace of first content information is inputted as the command to thereceiving communication means when the receiving communication means isreceiving the first content information through the connection formed inthe communication network, the receiving control means makes control soas to output a disconnection instruction for disconnecting theconnection for transmitting the first content information, which isformed in the communication network connecting the receivingcommunication means and the information providing apparatus, and aformation instruction for forming the connection for transmitting thesecond content information, which is formed in the communication networkconnecting the receiving communication means and the informationproviding apparatus, and characterized in that the information providingapparatus further includes detection means for detecting whether or notresource information indicating the communication band resource iscontained in an instruction signal, when the receiving communicationmeans providing communication means receives the instruction signal fromthe information receiving apparatus, and based on a detection resultfrom the detection means, the providing control means makes control soas to select a first mode in which a band reservation command forreserving the communication band resource is outputted and thecommunication means is controlled so as to output the contentinformation to the information receiving apparatus, if the instructionsignal does not contain the resource information, or a second mode inwhich the communication means is controlled so as to output the contentinformation with use of the communication band resource indicated by theresource information, if the instruction signal contains the resourceinformation.
 11. A system according to claim 10, further comprising arelay apparatus between the information providing apparatus and theinformation receiving apparatus, characterized in that the relayapparatus reserves the band communication resource based on aninstruction from the providing control means and the receiving controlmeans.
 12. A system according to claim 11, characterized in that therelay apparatus reserves the communication resource used forcommunication from the information providing apparatus to theinformation receiving apparatus.
 13. A content receiving apparatus forreceiving content data from a content server via a communicationsnetwork, the content receiving apparatus comprising: a communicationunit that receives content data and sends request messages; an inputunit that inputs a switch command, which switches the content receivingapparatus from a first content data to a second content data sent by thecontent server; and a controller that controls the communications unit;wherein in order to switch between the first content data and the secondcontent data, the controller controls the communication unit to send areservation release request message to the content server, whichreleases a first network connection, and a reservation instructionsignal to reserve a communication resource, and form a second connectionutilizing the communication resource, such that the second content datais received by the content receiving apparatus via the second networkconnection; and wherein if the controller recognizes a communicationnetwork resource which is necessary for receiving the content data, thecontroller controls the communication unit to output a reservationrequest message containing resource information indicating thecommunication network resource to utilize, and if the controller doesnot recognize a communication network resource which is necessary forreceiving the content data, the controller controls the communicationunit to output a reservation request message that does not containresource information indicating the communication network resource toutilize.
 14. A method for communications on a network between a contentserver and a content receiving terminal, the method comprising:receiving at the content receiving terminal data containing resourcereservation information sent by the content server; sending a networkresource reservation request message from the content receiving terminalto the content server to reserve a first network resource; receivingfirst content data at the content receiving terminal sent by the contentserver via the first network resource; and wherein when an input signalis received by the content receiving terminal to display second contentdata, sending a network resource release message from the contentreceiving terminal to the content server to release the first networkresource; sending a second network resource reservation request messageto reserve a second network resource; and receiving second content dataat the content receiving terminal sent by the content server via thesecond network resource; and wherein if a network resource which isnecessary for receiving content data is recognized by a control unit,then the network reservation request message includes resourceinformation indicating a network resource to utilize to receive thecontent data, otherwise if the network resource which is necessary forreceiving the content data is not recognized by the control unit, thenthe network reservation request message does not include resourceinformation.
 15. The method of claim 14, wherein the content receivingterminal automatically switches between different content data, after apredetermined period of time.
 16. A content server for providing contentdata for a content receiving apparatus via a communications network, thecontent server comprising: a communication unit that receives a requestmessage indicating a communication network resource and provides contentdata via the communication network resource; a storage unit that storescontent information; and a controller that makes a selection to outputcontent information stored in the storage unit to the content receivingapparatus, in response to a request to switch from a first content datato a second content data; wherein the controller releases a firstnetwork resource and reserves a second network resource such that thecommunication unit sends the second content data via the second networkresource; and wherein if the controller recognizes a communicationnetwork resource which is necessary for receiving the content data, thecontroller controls the communication unit to output a reservationrequest message containing resource information indicating thecommunication network resource to utilize, and if the controller doesnot recognize a communication network resource which is necessary forreceiving the content data, the controller controls the communicationunit to output a reservation request message that does not containresource information indicating the communication network resource toutilize.
 17. A method for communications on a network between a contentserver and a content receiving terminal, the method comprising: sendingdata containing resource reservation information from the content serverto the content receiving terminal; receiving a network resourcereservation request message sent from the content receiving terminal tothe content server to reserve a first network resource; sending firstcontent data from the content server to the content receiving terminalvia the first network resource; receiving the first content data on thecontent receiving terminal; and wherein when an input signal is receivedby the content receiving terminal to display second content data,receiving a network resource release message sent from the contentreceiving terminal to the content server to release the first networkresource; receiving a second network resource reservation requestmessage at the content server to reserve a second network resource;sending second content data to the content receiving terminal sent bythe content server via the second network resource; and receiving thesecond content data on the content receiving terminal; and wherein if anetwork resource which is necessary for receiving content data isrecognized by a control unit, then the network reservation requestmessage includes resource information indicating a network resource toutilize to receive the content data, otherwise if the network resourcewhich is necessary for receiving the content data is not recognized bythe control unit, then the network reservation request message does notinclude resource information.
 18. A content receiving apparatus forreceiving data, the content receiving apparatus comprising: acommunication unit configured to send a request message and to receivedata; an input unit configured to make a switch request and areservation request, wherein the switch request is made to release afirst network connection which is utilized to receive first contentdata, and the reservation request reserves a second network connectionin order to receive a second content data at the communication unit; anda control unit configured to control the communication unit to send theswitch request message and the reservation request message periodically;and wherein in order to switch between the first content data and thesecond content data, the controller controls the communication unit tosend a reservation release request message to the content server, whichreleases a first network connection, and a reservation instructionsignal to reserve a communication resource, and form a second connectionutilizing the communication resource, such that the second content datais received by the content receiving apparatus via the second networkconnection; and wherein if the control unit recognizes a communicationnetwork resource which is necessary for receiving the content data, thecontrol unit controls the communication unit to output a reservationrequest message containing resource information indicating thecommunication network resource to utilize, and if the control unit doesnot recognize a communication network resource which is necessary forreceiving the content data, the control unit controls the communicationunit to output a reservation request message that does not containresource information indicating the communication network resource toutilize.
 19. A method of switching between content data stored on acontent server and received over a communications network by a contentreceiving terminal, the method comprising: sending a switch requestmessage from the content receiving terminal to the content server torelease a first network connection and to stop transmission of firstcontent data sent over the first network connection; and sending areservation request message from the content receiving terminal to thecontent server to reserve a second network connection and to starttransmission of second content data over the second network connection;wherein the switch request message and the reservation request messageare sent periodically to switch between the stored content data.
 20. Aninformation receiving apparatus which is connected to an informationproviding apparatus by forming a connection in a communication networkand which receives content information from the information providingapparatus through the connection, comprising: an operating section forinputting a command based on an operation by a user; a communicationsection for making communication through the communication network; acontrol section for controlling the communication section so as tooutput an instruction signal, based on the command inputted through theoperating section; and a display section for displaying the contentinformation received by the communication means, characterized in thatif a switching instruction which indicates that second contentinformation should be received in place of first content information isinputted as the command to the communication section when thecommunication section is receiving the first content information throughthe connection formed in the communication network, the control sectionmakes control so as to output a service switching instruction forrequesting that the information providing apparatus provide the secondcontent information in place of the first content information, and thecommunication section subsequently receives the second contentinformation through the same connection through which the first contentinformation was received.
 21. An information providing apparatus whichis connected to an information receiving apparatus through acommunication network and which provides the information receivingapparatus with content information, with use of a communication bandresource of the communication network which is reserved prior toproviding of the content information, comprising: a communicationsection for making communication through the communication network; astorage unit for storing the content information; and a controller foroutputting a band reservation command for reserving the communicationband resource, for making control to provide first content informationthrough a communication band resource, and for making control to switchfrom providing the first content information to providing second contentinformation through the same communication band resource in response toreceiving a service switching instruction from the information receivingapparatus.
 22. The apparatus of claim 21, wherein the controllerincludes a CPU, ROM, and RAM.
 23. A method of providing contentinformation from an information server to an information receivingterminal through a communication network, with use of a communicationband resource of the communication network which is reserved prior toproviding of the content information, comprising: providing a servicefrom the information server to the information receiving terminalthrough the reserved communication band resource, including providingfirst content information to the information receiving terminal;receiving a service switching instruction at the information server fromthe information receiving terminal, indicating a change in service; andchanging the service provided from the information server to theinformation receiving terminal through the reserved communication bandresource according to the indicated change of service; wherein thechange of service indicates second content information, and furthercomprising: stopping providing the first content information; andproviding the second content information from the information server tothe information receiving terminal through the same reservedcommunication band resource that was used for providing the firstcontent information.
 24. The method of claim 23, further comprising:determining a quality of service appropriate to provide the secondcontent information through the reserved communication band resource;and changing the quality of service provided by the informationproviding apparatus according to the determined quality of service, ifdifferent from the quality of service appropriate for providing thefirst content information.
 25. The method of claim 23, wherein thechange of service indicates a change in quality of service, and furthercomprising: changing the quality of service provided by the informationproviding apparatus according to the indicated change of service.
 26. Acontent receiving apparatus for receiving content data from a contentserver via a communications network, the content receiving apparatuscomprising: a communication unit that receives content data and sendsrequest messages; an input unit that inputs a switch command, whichswitches the content receiving apparatus from a first content data to asecond content data sent by the content server; and a controller thatcontrols the communications unit; wherein in order to switch between thefirst content data and the second content data, the controller controlsthe communication unit to send a reservation release request message tothe content server, which releases a first network connection, and areservation instruction signal to reserve a communication resource, andform a second connection utilizing the communication resource, such thatthe second content data is received by the content receiving apparatusvia the second network connection; and wherein if the controllerrecognizes a communication network resource which is necessary forreceiving the content data, the controller controls the communicationunit to output a reservation request message containing resourceinformation indicating the communication network resource to utilize,and if the controller does not recognize a communication networkresource which is necessary for receiving the content data, thecontroller controls the communication unit to output a reservationrequest message that does not contain resource information indicatingthe communication network resource to utilize; and wherein thereservation release request message and the reservation request messageare sent together in one message.
 27. A method for communications on anetwork between a content server and a content receiving terminal, themethod comprising: receiving at the content receiving terminal datacontaining resource reservation information sent by the content server;sending a network resource reservation request message from the contentreceiving terminal to the content server to reserve a first networkresource; receiving first content data at the content receiving terminalsent by the content server via the first network resource; and whereinwhen an input signal is received by the content receiving terminal todisplay second content data, sending a network resource release messagefrom the content receiving terminal to the content server to release thefirst network resource; sending a second network resource reservationrequest message to reserve a second network resource; and receivingsecond content data at the content receiving terminal sent by thecontent server via the second network resource; wherein if a networkresource which is necessary for receiving content data is recognized bya control unit, then the network reservation request message includesresource information indicating a network resource to utilize to receivethe content data, otherwise if the network resource which is necessaryfor receiving the content data is not recognized by the control unit,then the network reservation request message does not include resourceinformation; and wherein the network resource release message and thenetwork resource reservation request message are sent together in onemessage.
 28. The method of claim 27, wherein the content receivingterminal automatically switches between different content data, after apredetermined period of time.
 29. A content server for providing contentdata for a content receiving apparatus via a communications network, thecontent server comprising: a communication unit that receives a requestmessage indicating a communication network resource and provides contentdata via the communication network resource; a storage unit that storescontent information; and a controller that makes a selection to outputcontent information stored in the storage unit to the content receivingapparatus, in response to a request to switch from a first content datato a second content data; wherein the controller releases a firstnetwork resource and reserves a second network resource such that thecommunication unit sends the second content data via the second networkresource, wherein controller sends releases the first network resourceand reserves the second network resource upon receipt of a singlerequest message; and wherein if the controller recognizes acommunication network resource which is necessary for receiving thecontent data, the controller controls the communication unit to output areservation request message containing resource information indicatingthe communication network resource to utilize, and if the controllerdoes not recognize a communication network resource which is necessaryfor receiving the content data, the controller controls thecommunication unit to output a reservation request message that does notcontain resource information indicating the communication networkresource to utilize.
 30. A method for communications on a networkbetween a content server and a content receiving terminal, the methodcomprising: sending data containing resource reservation informationfrom the content server to the content receiving terminal; receiving anetwork resource reservation request message sent from the contentreceiving terminal to the content server to reserve a first networkresource; sending first content data from the content server to thecontent receiving terminal via the first network resource; receiving thefirst content data on the content receiving terminal; and wherein whenan input signal is received by the content receiving terminal to displaysecond content data, receiving a network resource release message sentfrom the content receiving terminal to the content server to release thefirst network resource; receiving a second network resource reservationrequest message at the content server to reserve a second networkresource; sending second content data to the content receiving terminalsent by the content server via the second network resource; andreceiving the second content data on the content receiving terminal; andwherein if a network resource which is necessary for receiving contentdata is recognized by a control unit, then the network reservationrequest message includes resource information indicating a networkresource to utilize to receive the content data, otherwise if thenetwork resource which is necessary for receiving the content data isnot recognized by the control unit, then the network reservation requestmessage does not include resource information; and wherein the networkresource release message and the second network resource reservationrequest message are sent together in one message.
 31. A contentreceiving apparatus for receiving data, the content receiving apparatuscomprising: a communication unit configured to send a request messageand to receive data; an input unit configured to make a switch requestand a reservation request, wherein the switch request is made to releasea first network connection which is utilized to receive first contentdata, and the reservation request reserves a second network connectionin order to receive a second content data at the communication unit; anda control unit configured to control the communication unit to send theswitch request message and the reservation request message periodically;and wherein in order to switch between the first content data and thesecond content data, the controller controls the communication unit tosend a reservation release request message to the content server, whichreleases a first network connection, and a reservation instructionsignal to reserve a communication resource, and form a second connectionutilizing the communication resource, such that the second content datais received by the content receiving apparatus via the second networkconnection and wherein if the control unit recognizes a communicationnetwork resource which is necessary for receiving the content data, thecontrol unit controls the communication unit to output a reservationrequest message containing resource information indicating thecommunication network resource to utilize, and if the control unit doesnot recognize a communication network resource which is necessary forreceiving the content data, the control unit controls the communicationunit to output a reservation request message that does not containresource information indicating the communication network resource toutilize; and wherein the reservation release request message and thereservation request message are sent together in one message.
 32. Amethod of switching between content data stored on a content server andreceived over a communications network by a content receiving terminal,the method comprising: sending a switch request message from the contentreceiving terminal to the content server to release a first networkconnection and to stop transmission of first content data sent over thefirst network connection; and sending a reservation request message fromthe content receiving terminal to the content server to reserve a secondnetwork connection and to start transmission of second content data overthe second network connection; wherein the switch request message andthe reservation request message are sent periodically to switch betweenthe stored content data; wherein the switch request message and thereservation request message are sent together as one message.